Operator control device for a vehicle and method for operating such an operator control device

ABSTRACT

An operator control device for a vehicle, and a method for operating such an operator control device is disclosed. The operator control device is for controlling safety-relevant functions. To this end, the operator control device has at least one user interface having at least one user input panel for user input and a sensor system for identifying a user input in the area of the user input panel, wherein the sensor system has at least one capacitive sensor device having a first, electrically conductive sensor structure and a second, capacitive sensor device having a second, electrically conductive sensor structure, the sensor structures being arranged beneath the user interface in the area of the user input panel. The first sensor structure and the second sensor structure are each configured in comb-like and/or meanderous fashion and arranged in intermeshing fashion at least in a subarea of the user input panel.

The invention relates to an operator control device for a vehicle,particularly an operator control device for controlling safety-relevantfunctions, wherein the operator control device has at least one userinterface having at least one user input panel for user input and asensor system for identifying a user input in the area of the user inputpanel. In this case, the sensor system has at least one first,capacitive sensor device having a first, electrically conductive sensorstructure and a second, capacitive sensor device having a second,electrically conductive sensor structure, the sensor structures beingarranged beneath a user interface in the area of the user input panel.

Moreover, the invention relates to a method for operating an operatorcontrol device as described above.

Operator control devices having user interfaces having sensor systemshaving capacitive sensor devices for identifying a user input arefundamentally known from the prior art. In particular, operator controldevices having capacitive sensor devices for identifying a user inputare known that have an input screen as a user interface, for examplefrom DE 10 2011 011 769 A1 or DE 10 2007 039 609 A1.

In capacitive sensor devices, a user input is identified in this case onthe basis of what is known as the “capacitive principle”, which involvesan approach by a human hand or a finger, particularly contact with theuser interface, in the detection area of the associated sensorstructures causing a change in the capacitive coupling of the relevantsensor structure to the surroundings and, if present, to a referenceelectrode, the change in the capacitive coupling being able to beregistered by means of metrology. From the registered change in thecapacitive coupling of the sensor structure to the surroundings and/orto the reference electrode, it is then possible to infer a user input.To register the capacitive coupling of a sensor structure to thesurroundings and/or to a reference electrode or the change in acapacitive coupling, the prior art has various methods available. Theregistering of the capacitive coupling can fundamentally be measured, byway of example, by means of a resonant circuit or using a chargingprocess, in which a current change is registered, for example, or bymeans of other appropriate suitable methods. Furthermore, for otherapplications a method is known that has been developed by the company“Microchip”, what is known as the CVD (Capacitive Voltage Divider)method, which is based on a simple voltage measurement, what is known asthe CVD self method involving a change in the capacitive coupling of thesensor structures to the surroundings being registered, and what isknown as the CVD mutual method involving a change in the capacitivecoupling of the sensor structure to a reference electrode beingregistered.

In safety-relevant systems, it is important to identify an erroneousresponse from the sensors used for signal capture or from the signalpaths of said sensors promptly in order to be able to transfer thesystem to a safe state. In this context, the prior art discloses variousfault detection mechanisms, it being known practice, in particular tocapture the safety-relevant signals in redundant fashion, to which endat least one respective additional sensor is usually provided whoseexpected sensor signal is captured and evaluated as independently aspossible and can be plausibilized with the sensor signal of the othersensor using various methods, in particular by means of comparison. Ifthe sensor signal appears to be implausible, a fault state is identifiedand the system is transferred to the safe state.

Moreover, the prior art discloses the practice of purposely stimulatingthe individual sensors and comparing and plausibilizing the subsequentlygenerated and captured sensor signals with the expected signal values.

In particular in the case of operator control devices having at leastone input screen as a user interface, above all in the case oftouchscreens, correct identification of a user input is a greatchallenge, since, unlike in the case of mechanical user input devices orstandard switches, no mechanical operation is caused that can beidentified explicitly and easily by means of appropriate switches, butrather just a mere approach towards or unintentional contact with theinput screen can lead to a change in the capacitive coupling, even if nouser input is desired.

It is an object of the invention to provide an alternative user inputdevice and also an alternative method, in particular an improved userinput device and also an improved method, that provide a simple way ofallowing the control of safety-relevant functions, even in operatorcontrol devices having an input screen as a user interface, so that theoperator control device can be used to control safety-relevantfunctions.

This object is achieved by an operator control device according to theinvention and by a method according to the invention as claimed in therespective independent patent claims. Advantageous embodiments of theinvention are the subject matter of the dependent patent claims, thedescription and the figures.

An operator control device according to the invention is characterizedin that the first sensor structure and the second sensor structure areeach configured in comb-like and/or meanderous fashion and arranged inintermeshing fashion at least in a subarea of the user input panel.

Such a configuration of the individual sensor structures and thecomb-like arrangement thereof allows particularly advantageous redundantidentification of a user input to be achieved in a simple manner, sincetwo respective sensor structures are arranged in the area of a commoncontrol panel.

In one advantageous configuration of an operator control deviceaccording to the invention, the sensor structures in this case are eacharranged in a plane beneath the user interface in the area of the userinput panel, preferably in a plane parallel to the user interface,particularly in a common plane.

In a further advantageous configuration of an operator control deviceaccording to the invention, the user interface has multiple user inputpanels, wherein each user input panel has an associated sensor systemfor identifying a user input in the area of the associated user inputpanel. In this case, each sensor system associated with the user inputpanel preferably has at least one first, capacitive sensor device havinga first, electrically conductive sensor structure and a second,capacitive sensor device having a second, electrically conductive sensorstructure, the sensor structures in particular each being arrangedbeneath the user interface of the associated user input panel andpreferably each being configured in comb-like and/or meanderous fashionand arranged in intermeshing fashion in a subarea of the associated userinput panel.

That is to say that, as a preference, if the user interface has multipleuser input panels, each user input panel has an associated sensor systemas described above having at least one first capacitive sensor devicehaving a first sensor structure and a second capacitive sensor devicehaving a second sensor structure, the sensor structures each beingconfigured in comb-like and/or meanderous fashion and arranged inintermeshing fashion.

As a preference, at least one user interface is formed by at least oneinput screen in this case, each input screen being able to have multipleuser input panels.

As a preference, at least two first sensor structures or two secondsensor structures of two sensor systems are electrically connected toone another, and as a particular preference, the first sensor structuresor the second sensor structures are respectively connected to oneanother. As a result, the respective sensor structure that extends overmultiple sensor systems can be used for multiple sensor systems as acontrol sensor, as a result of which simple plausibilization of thecaptured sensor signals is possible in a particularly simple manner.

In a further advantageous configuration of an operator control deviceaccording to the invention, at least one sensor system is configured toregister, in comparison with a reference state, a respective change inthe capacitive coupling of the first sensor structure to thesurroundings and/or a reference electrode and a change in the capacitivecoupling of the second sensor structure to the surroundings and/or areference electrode, particularly a change in the capacitive couplingthat is caused as a result of a user input in the area of the user inputpanel.

In a particularly advantageous configuration of an operator controldevice according to the invention, the sensor system is configured suchthat to register the change in the capacitive coupling of at least onesensor structure to the surroundings, in a first scanning cycle areference capacitance and a measurement capacitance, formed by thesensor structure and the surroundings, can each be charged with adefined electrical potential in a first step, the reference capacitancebeing able to be charged with a first defined potential and themeasurement capacitance being able to be charged with a second, definedelectrical potential. Further, the sensor system is configured such thatthe reference capacitance and the measurement capacitance formed by thesensor structure and the surroundings can be shorted in a further step,and the resulting electrical potential arising between the measurementcapacitance and the reference capacitance can be registered as a sensorsignal in a further step, the resulting electrical potential arising onthe basis of the first and second electrical potentials and also on thebasis of the magnitude of the reference capacitance and on the basis ofthe magnitude of the measurement capacitance. In this case, themeasurement capacitance can be charged by virtue of a defined electricalpotential being applied to the sensor structure.

For particularly accurate registering of the change in the capacitivecoupling of the sensor structure to the surroundings, theabove-described first two steps of the first scanning cycle can berepeated in every detail.

In a further preferred configuration of an operator control deviceaccording to the invention, the sensor system is configured such that ina further scanning cycle, preferably in a second and/or third and/orfourth scanning cycle, the reference capacitance can be charged with thesecond electrical potential and the measurement capacitance can becharged with the first electrical potential in the first step, thereference capacitance and the measurement capacitance formed by thesensor structure and the surroundings can be shorted in a further step,and the resulting electrical potential arising between the measurementcapacitance and the reference capacitance can be registered as a sensorsignal in a further step, the resulting electrical potential arising onthe basis of the first and second potentials and also on the basis ofthe magnitude of the reference capacitance and on the basis of themagnitude of the measurement capacitance. That is to say that, as apreference, the relevant capacitances are charged inversely in a secondor a further scanning cycle that preferably follows the first scanningcycle. As a result, the registering accuracy can be improved stillfurther.

As a particular preference, in particular also, the first two steps ofthe last-described scanning cycle are repeated, since this allows evenbetter registering accuracy to be achieved, in particular a highersignal resolution. This is advantageous, in particular, if the internalreference capacitance is distinctly larger than the external capacitanceor if the internal reference capacitance is distinctly smaller than theexternal capacitance, that is to say if the reference capacitance andthe measurement capacitance have distinctly different magnitudes.

In a particularly advantageous configuration of an operator controldevice according to the invention, at least one sensor system has areference electrode, in particular additionally, wherein the referenceelectrode can have a defined electrical potential applied to it and thesensor system is configured such that a user input in the area of theuser input panel causes a registerable change in the capacitive couplingof the sensor structure of the reference electrode in comparison with areference state. Preferably, the sensor system is configured to registerthis change in the capacitive coupling of the sensor structure to thereference electrode.

In a further advantageous configuration of an operator control deviceaccording to the invention, the sensor system is configured such that ina further scanning cycle, preferably in a second and/or third and/orfourth scanning cycle, in particular additionally, the referenceelectrode can have a defined electrical potential applied to it in afirst step, and the capacitive coupling of at least one sensor structureto the reference electrode can be registered in a further step.

It has been found to be particularly advantageous in this case if theoperator control device or at least one sensor system is configured toregister the change in the capacitive coupling of at least one sensorstructure to the surroundings and the change in the capacitive couplingof this sensor structure to the reference electrode in succession,preferably in turn, in particular alternately, wherein preferably, inparticular for the purpose of signal plausibilization and/or for thepurpose of evaluation of whether a user input has been made, theascertained changes in the capacitive couplings can each be offsetagainst one another.

By way of example, a change in the capacitive coupling of at least onesensor structure to the surroundings can be registered over two scanningcycles and subsequently a change in the capacitive coupling of thissensor structure to the reference electrode or to the surroundings andthe reference electrode can be registered over two scanning cycles, theorder naturally being arbitrary.

Such combined registering of the capacitive coupling of at least onesensor structure, namely firstly to the surroundings and secondly to thereference electrode or to the surroundings and the reference electrode,allows the registering accuracy to be increased considerably. Inparticular, the resolution, above all the sensitivity of the sensordevice or the accuracy therefor, can be distinctly improved thereby.Moreover, measurement errors and steady-state offsets or the like can beremoved in a simple manner.

In a further advantageous configuration of an operator control deviceaccording to the invention, at least one sensor structure of at leastone sensor system can also be connected and operated as a referenceelectrode. Preferably, both the first sensor structure and the secondsensor structure can be connected as a reference electrode, inparticular in turn. In this case, the second sensor structure canpreferably be operated as a reference electrode if the change in thecapacitive coupling of the first sensor structure is registered, andvice versa. If the sensor system has more than two sensor structures,preferably all of the sensor structures are each connectable andoperable as a reference electrode. Therefore, no additional electrode isrequired for the reference electrode, which allows particularlyinexpensive manufacture of an operator control device according to theinvention.

In a further advantageous configuration of an operator control deviceaccording to the invention, at least one sensor system has a screeningdevice having at least one screening element, wherein the screeningdevice is configured to screen the first sensor device and/or the secondsensor device from perturbing capacitive couplings to components of theoperator control device. In this case, the screening element ispreferably formed by an electrically conductive screening structure thatis arranged in particular between the electrical sensor structure of thefirst sensor device and the second sensor structure of the second sensordevice of the sensor system. In particular, it has been found to beadvantageous if the screening device is formed by an electricalconductor or an electrode structure that runs, preferably in meanderingfashion, between the first sensor structure and the second sensorstructure.

In a particularly advantageous configuration of an operator controldevice according to the invention, the screening element can have adefined, electrical potential, preferably a potential that is at leastsometimes tracked to a potential applied to the sensor structure duringthe registering of the change in the capacitive coupling of the sensorstructure, particularly a potential that follows the profile of thepotential applied to the sensor structure, applied to it duringregistering of the change in the capacitive coupling of at least onesensor structure.

In a further advantageous configuration of an operator control deviceaccording to the invention, at least one sensor structure of at leastone sensor system can also be connected as an active screening element,wherein preferably the first sensor structure and the second sensorstructure can each be connected as an active screening element, inparticular in turn. If the sensor system has more than two sensorstructures, then preferably all of the sensor structures are eachconnectable and operable as an active screening element. In this manner,it is not necessary to provide an additional screening element, whichallows particularly inexpensive manufacture of an operator controldevice according to the invention.

In a preferred configuration of an operator control device according tothe invention, at least one sensor system has not only the firstcapacitive sensor device and the second capacitive sensor device butalso at least one further sensor device for identifying a user input inthe area of the user input panel associated with the sensor system,preferably a pressure-sensitive sensor device, such as a microswitch, arubber mat contact, a pressure contact or a force sensor, for example.In this manner, threefold-redundant identification of a user input ispossible and the probability of misidentification by the two capacitivesensor devices is distinctly reduced and therefore the safety of theoperator control device is increased.

In a particularly advantageous configuration, in particular to meetcertain safety requirements, at least one sensor system is configured toregister the change in the capacitive coupling of the sensor structureof the first capacitive sensor device and of the sensor structure of thesecond sensor device of the sensor system to the surroundings and/or toa reference electrode at the same time or to register said change atsuch slightly staggered times that safety-relevant plausibilization ofthe captured sensor signals is possible.

In a further advantageous configuration of an operator control deviceaccording to the invention, at least one sensor system is configured toregister the change in the capacitive coupling of the sensor structureof a capacitive sensor device to the surroundings and/or to a referenceelectrode only if a user input has been identified beforehand during theregistering of the change in the capacitive coupling of the sensorstructure of the other capacitive sensor device to the surroundingsand/or to a reference electrode. That is to say, in other words, that inan advantageous configuration of an operator control device according tothe invention, the change in the capacitive coupling of the secondsensor structure, for example, is registered only if a user input hasbeen identified beforehand by means of the first sensor device. In thismanner, a wake-up circuit can be realized with only one sensor device,which allows the power consumption of the operator control device to bereduced by almost all half, particularly in standby mode.

In a particularly advantageous configuration, particularly for thecontrol of safety-relevant functions, the operator control device has amonitoring device for identifying a fault state in at least one sensorsystem, wherein the monitoring device is configured to plausibilize atleast one captured sensor signal of at least one sensor device of thesensor system, particularly to plausibilize the sensor signals of allthe sensor devices of the sensor system. In this case, the monitoringdevice identifies a fault if at least one captured and evaluated sensorsignal of the sensor system is implausible, the monitoring devicepreferably being configured to take at least one captured sensor signalof the first sensor device and at least one captured sensor signal ofthe second sensor device and/or to take the directly successivelyregistered changes in the capacitive coupling of a sensor structure tothe surroundings and in the capacitive coupling of this sensor structureto the reference electrode as a basis for identifying whether there is afault state.

That is to say, in other words, that, as a preference, there is firstprovision for plausibilization by means of at least one captured sensorsignal of the first sensor device by comparison with at least one sensorsignal of the second sensor device and/or on the basis of the registeredchanges in the capacitive coupling of a sensor structure to thesurroundings and the reference electrode.

Preferably, the monitoring device is, in particular additionally,configured to identify reciprocal influencing of the first sensor deviceand the second sensor device of at least one sensor system, inparticular a short circuit between the first sensor structure and thesecond sensor structure, the operator control device preferably beingconfigured to output a fault state if influencing is identified.

In a further advantageous configuration of an operator control deviceaccording to the invention, the monitoring device is configured toidentify an inadmissible signal value of at least one of the sensorsignals, preferably of all of the sensor signals, the monitoring devicebeing, in particular, configured to identify a measured value rangeovershoot and/or an inadmissible signal value within a measured valuerange. Preferably, the operator control device is in this case likewiseconfigured to output a fault state if an inadmissible signal value isidentified.

In a further advantageous configuration of the operator control device,the monitoring device is configured to identify whether one of thecaptured sensor signals is constant for longer than a predefined period,that is to say has not changed. This fault detection is normally alsoreferred to as timeout identification, wherein preferably, if a timeoutis identified, an error message can be sent and the system can betransferred to a safety state.

In a further advantageous configuration of an operator control deviceaccording to the invention, a signal filter device for filtering thecaptured signals is further provided in order to achieve betterevaluation quality.

In a particularly advantageous configuration, the operator controldevice has a lighting device having at least one light-emitting sourcefor lighting the back of at least one user input panel, wherein the atleast one light-emitting source is preferably arranged in a planebeneath at least one sensor structure of the sensor system associatedwith the control panel. In this case, the light-emitting source ispreferably arranged beneath the sensor structure of the first capacitivesensor device and beneath the sensor structure of the second capacitivesensor device of the sensor system associated with the control panel.

As a preference, the light-emitting source is arranged on a printedcircuit board in this case and the sensor structure is in a planeoriented, above the printed circuit board, preferably parallel to theprinted circuit board plane. The first and second sensor structures mayin this case be arranged on a back of the component forming the userinterface, for example on the back of a glass plate forming the userinterface, or else on a separate layer that may be formed by a furtherglass plate or a thin transparent film or a plastic cap or the like, forexample.

As a particular preference, at least one sensor structure of the sensorsystem, preferably the first and the second sensor structure, that is tosay both sensor structures, in particular all the structures of thesensor system, are configured and/or arranged such that a beam path fromthe at least one light-emitting source to the control panel is notblocked.

That is to say, in other words, that at least one sensor structure,preferably all of the structures of the sensor system, are arranged andconfigured such that the light emitted by the light-emitting source canradiate to the user input panel unimpeded. In this case, preferably allof the other structures, such as the reference electrode or thescreening element, for example, are also configured and/or arrangedaccordingly. Further, the individual components of the operator controldevice should be configured and arranged such that a display produced inthis manner in the area of the control panel is readable, in particularhighly readable. That is to say that the individual components should beconfigured and arranged and coordinated with one another such that, inparticular, a good contrast with the display can be ensured andsufficient sharpness.

In a further advantageous configuration of an operator control deviceaccording to the invention, at least one sensor structure of the sensorsystem, preferably the first and the second sensor structure, inparticular all the structures, are configured in such a transparentfashion that they are transmissive at least for a portion of theradiation emitted by the at least one light-emitting source, i.e. inother words that at least one sensor structure is configured such thatsufficient emitted light from the light-emitting source can reach thecontrol panel in order to light it from the back.

In a particularly advantageous configuration, at least one sensorstructure is manufactured from indium tin oxide or comprises indium tinoxide.

Indium tin oxide, frequently also abbreviated to ITO, is asemiconductive substance that is largely transparent in visible light.It is a mixed oxide that is usually made up of 90% indium (III) oxide(In₂O₃) and 10% tin (IV) oxide (SnO₂). Indium tin oxide is usuallyapplied to substrates under a high vacuum. The substrates used are inparticular glass and plastic films. Normally, application is effected bymeans of cathode sputtering. Indium tin oxide can alternatively beapplied by thermal evaporation, components subjected tovapour-deposition needing to be heated to up to 360° C., which limitsapplicability above all for plastics.

A further possibility is the sol-gel method, which can be used on thinbut extensive layers. In this case, the substrates can be dipped,sprayed, printed or spin-coated. Instead of indium tin oxide, at leastone sensor structure may alternatively be manufactured from or comprisefluorine-doped tin oxide (FTO), aluminium-doped tin oxide (AZO) orantimony-doped tin oxide (ATO) or graphene. These materials have theadvantage over indium tin oxide that they are much less expensive.

A method according to the invention for operating an operator controldevice, preferably for operating an above-described operator controldevice according to the invention, wherein the operator control devicehas at least one user interface having at least one user input panel foruser input and a sensor system for identifying a user input in the areaof the user input panel, wherein the sensor system has at least onefirst, capacitive sensor device having a first, electrically conductivesensor structure and a second, capacitive sensor device having a second,electrically conductive sensor structure, the sensor structures beingarranged beneath the user interface in the area of the user input panel,is characterized in that to identify a user input, the change in thecapacitive coupling of the first sensor structure to the surroundingsand/or a reference electrode and a change in the capacitive coupling ofthe second sensor structure to the surroundings and/or a referenceelectrode is registered. In this case, to register the change in thecapacitive coupling of at least one sensor structure, preferably bothsensor structures, to the surroundings, in a first scanning cycle, areference capacitance and a measurement capacitance, formed by thesensor structure and the surroundings, are each charged with a definedelectrical potential, the reference capacitance being charged with afirst, defined electrical potential and the measurement capacitancebeing charged with a second, defined electrical potential, in a firststep. The reference capacitance and the measurement capacitance formedby the sensor structure and the surroundings are shorted in a furtherstep, and the resulting electrical potential arising between themeasurement capacitance and the reference capacitance is registered as asensor signal in a further step. The resulting electrical potentialarises in this case on the basis of the first and second electricalpotentials and also on the basis of the magnitude of the referencecapacitance and on the basis of the magnitude of the measurementcapacitance.

In one advantageous embodiment of a method according to the invention,the first two steps of the first scanning cycle are repeated before thereference capacitance and the measurement capacitance are shorted. Thisallows particularly high registering accuracy to be achieved.

In a further advantageous embodiment of a method according to theinvention, in a further scanning cycle, preferably in a second and/orthird and/or fourth scanning cycle, the reference capacitance is chargedwith the second electrical potential and the measurement capacitance ischarged with the first electrical potential in the first step. In afurther step, the reference capacitance and the measurement capacitanceformed by the sensor structure and the surroundings are subsequentlyshorted and, in a further step, the resulting electrical potentialarising between the measurement capacitance and the referencecapacitance is registered as a sensor signal, the resulting electricalpotential also arising in this scanning cycle on the basis of the firstand second potentials and also on the basis of the magnitude of thereference capacitance and on the basis of the magnitude of themeasurement capacitance.

If the sensor system has a reference electrode and if the sensor systemis configured such that a user input in the area of the user input panelcauses a registerable change in a capacitive coupling of the sensorstructure to the reference electrode in comparison with a referencestate, then preferably in a further scanning cycle, in particular in asecond and/or third and/or fourth scanning cycle, in particularadditionally, the reference electrode has a defined electrical potentialapplied to it in a first step, and the capacitive coupling of the sensorstructure to the reference electrode is registered in the further step.

As a particular preference, the change in the capacitive coupling of asensor structure to the surroundings and the change in the capacitivecoupling of this sensor structure to the reference electrode arerespectively registered in succession, preferably in turn, in particularalternately.

Preferably, at least one sensor structure of at least one sensor systemis at least intermittently connected and operated as a referenceelectrode in this case, while the capacitive coupling of another sensorstructure is registered, wherein preferably all of the sensor structuresof the sensor system, in particular alternately in turn, arerespectively connected as a reference electrode.

If the sensor system has at least one screening device having at leastone electrically conductive screening element for screening the firstsensor device and/or the second sensor device from perturbing capacitivecouplings to components of the operator control device, the screeningelement preferably has a defined, electrical potential, preferably apotential that is at least sometimes tracked to a potential that isapplied to the sensor structure during the registering of the change inthe capacitive coupling of the sensor structure, particularly apotential that follows the profile of the potential applied to thesensor structure, applied to it during registering of the change in thecapacitive coupling of at least one sensor structure of the sensorsystem.

In one advantageous embodiment of a method according to the invention,at least one sensor structure of at least one sensor system is at leastintermittently operated as an active screening element in this case,preferably all of the sensor structures of a sensor system, inparticular in turn, are respectively operated as a screening element, arespective sensor structure having a potential applied to it that is atleast sometimes tracked to a potential applied to the other sensorstructure during the registering of the change in the capacitivecoupling of the other sensor structure, in particular follows thispotential.

Preferably, the change in the capacitive coupling of the sensorstructure of the first capacitive sensor device and of the sensorstructure of the second capacitive sensor device of the sensor system tothe surroundings and/or to a reference electrode are registered at thesame time or at such slightly staggered times that safety-relevantplausibilization of the captured sensor signals is possible, whereinpreferably a user input in a user input panel is registered by means ofall the sensor devices of the sensor system associated with the userinput panel at the same time or at slightly staggered times.

That is to say, in other words, that preferably all of the sensordevices of a sensor system that are associated with a user input panelare used at the same time to identify a user input or are evaluated atsuch slightly staggered times that safety-relevant plausibilization ofthe captured sensor signals is possible.

In a particularly advantageous embodiment of a method according to theinvention, the change in the capacitive coupling of the sensor structureof a sensor device to the surroundings and/or to a reference electrodeis registered only if a user input has been identified beforehand bymeans of a further sensor device, in particular by means of the othercapacitive sensor device.

Preferably, when a user input on a user input panel is identified, afunction associated with the user input panel is triggered, the functionbeing triggered in particular only if no fault state in the sensorsystem and/or in the operator control device has been identified.

If the user interface of the operator control device has multiple userinput panels, wherein each user input panel has an associated sensorsystem for identifying a user input in the area of the associated userinput panel, wherein each sensor system associated with a user inputpanel has at least one first, capacitive sensor device having a first,electrically conductive sensor structure and a second, capacitive sensordevice having a second, electrically conductive sensor structure, andthe sensor structures each being arranged beneath the user interface ofthe associated user input panel, when a user input has been identified,a function is triggered only if the user input has been identified onlyin a single user input panel of the user interface. That is to say thatwhen a user input has been identified in multiple user input panels, nofunction is triggered. Alternatively, it is naturally also possible fora function to be triggered only if a user input is identified inmultiple, defined user input panels.

If the operator control device has a monitoring device for identifying afault state in at least one sensor system, then preferably themonitoring device is used to plausibilize at least one sensor signal ofat least one sensor device of at least one sensor system, wherein afault state is identified if at least one captured and evaluated sensorsignal is implausible, a fault state preferably being identified if atleast one captured sensor signal of the first sensor device isimplausible by comparison with at least one captured sensor signal ofthe second sensor device and/or if the directly successively registeredchanges in the capacitive coupling of at least one sensor structure tothe surroundings and in the capacitive coupling of this sensor structureto the reference electrode are implausible.

Preferably, a function is triggered only if all of the sensor signals ofthe sensor devices of a sensor system are plausible, to which end thecaptured sensor signals are preferably ANDed.

Such evaluation is naturally not limited to the first capacitive sensordevice and the second capacitive sensor device, but rather it ispossible in particular for further sensor devices, such as in particularpressure-sensitive sensor devices, for example force sensors, rubber matsensors, microswitches, etc., to be taken into consideration as well.

Preferably, a fault state in at least one sensor system, in particularas a result of reciprocal influencing of the first sensor structure andthe second sensor structure, is identified by virtue of a short-circuittest being performed, with a fault state being identified in the eventof a positive result. In order to perform the short-circuit test, adefined potential is preferably applied to one sensor structure and thepotential of the other sensor structure is registered. If the registeredpotential corresponds to the applied potential, then short circuit canbe assumed, whereas there is no short circuit if the potentials aredifferent.

Preferably, the short-circuit test described above is performed not onlyto register reciprocal influencing of the first and second sensorstructures, particularly to register a short circuit between the firstand second sensor structures, but rather in each case also to checkwhether there is a short circuit between one of the sensor structuresand another component, for example earth (GND), the supply voltage oranother line structure. To this end, the potential of the sensorstructure to be checked and the present potential of the associatedstructure are preferably each registered accordingly. If the potentialregistered on the sensor structure to be checked corresponds to thepotential of the respective structure, for example the earth electrode,the supply voltage electrode or the like, then there is possibly a shortcircuit with the relevant structure, whereas there is no short circuitif the potentials are different.

In a further advantageous embodiment of a method according to theinvention, a fault state in at least one sensor system is identified,preferably an inadmissible signal value of at least one of the sensorsignals is identified, in particular a measured value range overshootand/or an inadmissible signal value in a measured value range isidentified, by virtue of the captured signal value of at least onesensor signal being compared with admissible signal values, wherein afault state is identified if an inadmissible signal value is identified.

Moreover, one advantageous embodiment of a method according to theinvention can involve a fault state being identified by virtue of acheck being performed to determine whether one of the captured sensorsignals is constant for longer than a predefined period, that is to sayhas not changed during this period, with the fault state beingidentified if at least one of the captured signals is constant forlonger than the predefined period. In this way, what is known as timeoutidentification can be performed.

Further features of the invention are evident from the claims, thefigures and the description of the figures. All features and featurecombinations mentioned above in the description and the features andfeature combinations mentioned below in the description of the figuresand/or shown in the figures alone are usable not only in the combinationrespectively indicated but also in other combinations or else bythemselves.

Some of the cited features and properties relate both to an operatorcontrol device according to the invention and to a method according tothe invention. Some of these features and properties are sometimesdescribed only once, but apply, independently of one another within theframework of technically possible configurations, both to an operatorcontrol device according to the invention and to a method according tothe invention. The preferred embodiments, and advantages thereof,presented with reference to the operator control device thereforeaccordingly also apply to a method according to the invention, and viceversa.

The invention will now be explained in more detail on the basis ofpreferred exemplary embodiments, particularly with reference to theaccompanying drawings, in which.

FIG. 1 shows a schematic depiction of a section through an exemplaryembodiment of an operator control device according to the invention,

FIG. 2 schematically shows a plan view of the configuration andarrangement according to the invention of the sensor structures of thecapacitive sensor devices of the operator control device according tothe invention from FIG. 1,

FIG. 3 schematically shows a possible, alternative configuration andarrangement of the sensor structures for an alternative exemplaryembodiment of an operator control device according to the invention,

FIGS. 4 to 6 schematically show possible, alternative configurations andarrangements of the sensor structures for an alternative exemplaryembodiment of an operator control device according to the invention,

FIG. 7 shows a detail from a schematic block diagram of a capacitivesensor device for an operator control device according to the inventionin order to clarify the manner of operation of the capacitive sensordevice,

FIG. 8 shows a detail from a schematic block diagram of a sensor systemof the operator control device according to the invention from FIG. 1,

FIG. 9 schematically shows the profile of the electrical potentialapplied to a sensor structure of the operator control device accordingto the invention during the registering of a change in the capacitivecoupling of a sensor structure to the surroundings,

FIG. 10 schematically shows the profile arising in contrast to FIG. 9for the electrical potential applied to the sensor structure of thecapacitive sensor device when steps T1 and T2 and also T4 and T5 arerespectively repeated during the registering of the change in thecapacitive coupling,

FIG. 11 shows an advantageous profile of a tracked electrical potentialof an active screening element,

FIG. 12 shows a particularly advantageous profile of an electricalpotential of an active screening element, the potential of the screeningelement in this case, in contrast to FIG. 10, following the profile ofthe electrical potential applied to the sensor structure.

FIG. 1 shows an exemplary embodiment of an operator control device 10according to the invention having an input screen 11 as a user interface12, a user input being possible by using a finger 13 to touch the userinterface 12 in the manner of a keystroke. In this case, the operatorcontrol device 10 according to the invention is provided for the purposeof controlling various, including safety-relevant, functions in avehicle.

This exemplary embodiment of an operator control device 10 according tothe invention has a sensor system having multiple sensor devices 14 a,14 b and 16, the sensor devices 14 a and 14 b each being capacitivesensor devices 14 a, 14 b while the sensor device 16 is apressure-sensitive sensor device in the form of a force sensor.

The sensor devices 14 a, 14 b and 16 of the sensor system of theoperator control device according to the invention are eachelectronically coupled to a printed circuit board, the printed circuitboard having a microcontroller—not depicted here—for evaluating thecaptured sensor signals.

From FIG. 2, which schematically shows a plan view of the configurationand arrangement according to the invention of the sensor structures 19and 20 of the capacitive sensor devices of the operator control deviceaccording to the invention from FIG. 1, it is possible to see that thecapacitive sensor devices 14 a and 14 b each have a sensor structure 19and 20, respectively, beneath a user input panel 18 associated with thesensor devices 14 a and 14 b, the first capacitive sensor device 14 ahaving the sensor structure 19 associated with it and the sensorstructure 20 being associated with the capacitive sensor device 14 b.The sensor structures 19 and 20 in this arrangement are each mounted onthe back of the glass plate of the input screen 11 that forms the userinterface 12.

According to the invention, the first sensor structure 19 and the secondsensor structure 20 in this arrangement are each formed by electricalconductors configured in comb-like fashion that are arranged inintermeshing fashion in a common plane parallel to the user interface12.

The first sensor device 14 a and the second capacitive sensor device 14b in this arrangement are each configured to identify a touch of theuser interface 12 in a respective common user input panel 18 associatedwith the two sensor devices 14 a and 14 b, whereas thepressure-sensitive sensor device 16 does not react just to mere touchingof the user interface 12, but rather reacts only when the finger 13 isused to apply a pressure exceeding a threshold value to the userinterface 12 or the associated user input panel.

The identification of a user input by means of the capacitive sensordevices 14 a, 14 b is effected on the basis of what is known as the“capacitive principle” in this case, which involves an approach by ahuman hand or a finger 13, in particular a touch of the user interface12, in the detection area of the associated sensor devices 14 a, 14 bcausing a change in the capacitive couplings of the relevant sensorstructures 19, 20 to the surroundings and, if present, to a referenceelectrode, the change in the capacitive coupling being able to beregistered by metrology. From the registered changes in the capacitivecouplings of the sensor structures 19, 20 to the surroundings and/or tothe reference electrode, it is then possible to infer a user input.

In this exemplary embodiment of an operator control device according tothe invention, the user interface 12 is further lit, the lighting of theuser interface 12 being provided by a light-emitting source 17 arrangedat the back in the form of an LED that is configured to illuminate theuser interface 12 from the back, the user interface 12 being ofaccordingly transparent configuration, so that the light is alsoperceived as lighting by a user.

So that the rays of light emitted by the light-emitting source are notblocked by the sensor devices 14 a and 14 b, in particular the sensorstructures 19, 20 thereof, the latter are of accordingly translucentconfiguration and in particular manufactured from indium tin oxide andvapour-deposited on the back of the user interface 12.

The respective comb-like configuration according to the invention andthe meshing arrangement of the first sensor structure 19 and the secondsensor structure 20 beneath an associated, common user input panel 18allows redundant registering of a user input in a simple manner, thesensor structures 19 and 20 being arranged at such a short distance fromone another that every user input results in a change in the capacitivecoupling of the two sensor structures 19, 20 to the surroundings and/ora reference electrode. The microcontroller—not denoted in more detailhere—on the printed circuit board 15 can be used to evaluate the twocaptured sensor signals of the first sensor device 14 a and the secondsensor device 14 b in parallel. In particular, a redundant evaluationrequired for safety-relevant functions is possible, the captured sensorsignals first being able to be compared with one another and secondlybeing able to be used for reciprocal plausibilization.

The sensor structures 19 and 20 in this arrangement are used not onlyfor registering capacitive coupling to the surroundings and/or to areference electrode, not depicted here, but rather can furthermore atleast each be connected as an active screening element and as areference electrode.

FIG. 3 schematically shows a possible, alternative configuration andarrangement of the sensor structures 19 and 20 for an alternativeexemplary embodiment of an operator control device according to theinvention, wherein in this exemplary embodiment the input screen 11 hastwo user input panels 18, each user input panel 18 having an associatedsensor system with in each case a first sensor structure 19 and a secondsensor structure 20. The sensor structures 19 and 20 of a sensor systemare each arranged beneath the associated user input panel 18 and eachconfigured in comb-like fashion and each arranged in intermeshingfashion, so that respective redundant registering of a user input bymeans of the first sensor structure 19 and the second sensor structure20 is possible in each user input panel 18.

To simplify the design of an operator control device according to theinvention, the first sensor structures 19 are respectively connected toone another, so that only one connection contact is necessary forelectrical coupling to the printed circuit board 15 and themicrocontroller. A further advantage of a common sensor structure 19 isthat this sensor structure 19 can be used as a control sensor for all ofthe sensor systems of the operator control device 10 at the same time,which allows particularly simple and effective plausibilization of thecaptured sensor signals.

FIGS. 4 to 6 schematically show further possible, alternativeconfigurations and arrangements of the sensor structures 19 and 20 foran operator control device according to the invention, the sensor systemshown in FIG. 4 having a meanderously configured, further electricalconductor 21 provided between the first sensor structure 19 and thesecond sensor structure 20, which further electrical conductor islikewise arranged in the same plane as the first sensor structure 19 andthe second sensor structure 20 in this exemplary embodiment and isconnectable and can be operated as an active screening element. To thisend, the electrical conductor 21 can in particular have a defined,electrical potential UAE applied to it that is tracked to or follows thesensor signal applied to one of the sensor structures 19 and 20, whilethe change in the capacitive coupling of at least one sensor structure19 or 20 to the surroundings and/or to a reference electrode, notdepicted here, is registered, cf. FIGS. 11 and 12.

In the case of the sensor structures 19 and 20 shown in FIG. 5, incontrast to the previous exemplary embodiments, the sensor structure 20is not configured in comb-like fashion like the sensor structure 19, butrather is meanderous, but, according to the invention, likewise arrangedso as to mesh with the first sensor structure 19.

FIG. 6 shows a further exemplary embodiment for the configuration andarrangement of the sensor structures 19, 20 of an operator controldevice according to the invention, with the first sensor structure 19and the second sensor structure 20 each being configured meanderously inthis case, but likewise, according to the invention, being arranged inintermeshing fashion.

In the case of the operator control device according to the inventiondescribed above, a user input is identified first by means of thepressure-sensitive sensor device 16 and also by means of the firstcapacitive sensor device 14 a and the second capacitive sensor device 14b using a method according to the invention.

To clarify the manner of operation of the capacitive sensor devices 14 aand 14 b, particularly to explain the method according to the invention,FIG. 7 shows a detail from a schematic block diagram of a capacitivesensor device for an operator control device according to the invention.An associated, exemplary potential profile—arising when a methodaccording to the invention is used—of a potential U_(Sensor) applied toa sensor structure 19 is depicted in FIG. 9.

A user input is identified, in particular the capacitive coupling of asensor structure is registered, using a method according to theinvention, which is subsequently described by way of example on thebasis of the sensor structure 19, by virtue of, during a first scanningcycle AZ1, the reference capacitance 22 and the sensor structure 19capacitively coupled to the surroundings being charged in definedfashion in a first step in the period T1, for example the referencecapacitance being charged with 5V and the sensor structure 19, as shown,with 0V, and subsequently the reference capacitor 22 and the sensorstructure 19 being shorted in a second step T2. In a third step in aperiod T3, an evaluation device 23, which in this exemplary embodimentis the microcontroller arranged on the printed circuit board, thenregisters and evaluates the potential U_(Sensor) arising between thereference capacitance 22 and the sensor structure 19. From the potentialU_(Sensor) arising on the sensor structure 19, which potential conveysthe capacitive coupling of the sensor structure 19 to the surroundings,it is subsequently possible to infer whether or not there is a humanhand or a finger 13 etc. in the detection area of the sensor device 14 aor whether or not a user input has been made.

The reference capacitance 22 is charged by virtue of first of all theswitches SW1 and SW3 being closed and the switch SW2 being opened. Themeasurement capacitance C_(Surroundings) is charged by virtue of theswitches SW3 and SW1 being opened and the switch SW2 being closed. Oncethe measurement capacitance C_(Surroundings) is charged, the switch SW2is subsequently likewise opened again.

The shorting is then effected by closing the switch SW3 and causes thesame potential U_(Sensor) to arise on the reference capacitance 22 andthe measurement capacitance C_(Surroundings), the resulting electricalpotential U_(Sensor) fundamentally arising on the basis of the first andsecond electrical potentials and also on the basis of the magnitude ofthe reference capacitance 22 and on the basis of the magnitude of themeasurement capacitance C_(Surroundings). If the measurement capacitanceC_(Surroundings) is of approximately the same magnitude as the referencecapacitance 22, then approximately a potential U_(Sensor) of half theamplitude arises, i.e. in this case an amplitude of 5V prompts apotential of approximately 2.5V to arise on the sensor structure 19.

If there is no human hand or no finger 13 or the like in the detectionarea of the sensor device or of the sensor structure 19, then apotential profile U_(Sensor1) arises. If, by contrast, there is a humanhand or a finger 13 or the like in the detection area of the sensorstructure 19, then a different potential profile is obtained, depictedhere by the potential profile U_(Sensor2) by way of example. From thepotential U_(Sensor1) or U_(Sensor2) that is obtained, it is possible toinfer the presence or absence of a human hand 13 in the detection areaof the sensor structure 19.

During the registering of the potential U_(Sensor) applied to the sensorstructure 19 and to the reference capacitance 22, it is possible, if theswitch SW3 is open again, for the sensor structure 19 to already have adefined potential applied to it again, for example for a next scan toidentify a user input or for another purpose.

To further improve registering accuracy, it is additionally possiblefor, in a second scanning cycle AZ2, the reference capacitance 22 alsoto be subsequently charged with the second electrical potential of 0Vand for the measurement capacitance C_(Surroundings) to be charged withthe first electrical potential of 5V in the first step T4, that is tosay conversely with respect to the first scanning cycle AZ1.

In a further step T5, the reference capacitance 22 and the measurementcapacitance C_(Surroundings) formed by the sensor structure 19 and thesurroundings are then shorted again and, in a further step T6, it isagain possible for the resulting electrical potential U_(Sensor) arisingbetween the measurement capacitance C_(Surroundings) and the referencecapacitance 22 to be registered.

As a result, potential differences ΔU1 and ΔU2 are obtained that can beevaluated, instead of absolute potential values U_(Sensor1) andU_(Sensor2), which allows better identification accuracy to be attained.In particular, it is no longer necessary in this case to correct orremove perturbing, steady-state, capacitive couplings affecting theabsolute potential values U_(Sensor1) and U_(Sensor2), or to calibratethe sensor device 14 a, 14 b accordingly in this regard.

To increase registering accuracy, particularly to improve the resolutionfor measurement and reference capacitances 22 of different magnitude, itis advantageous to repeat the first two steps T1 and T2 and also T4 andT5 of the first scanning cycle AZ1 and of the second scanning cycle AZ2in each case, see FIG. 10, since in this manner the resulting potentialU_(Sensor) approaches half the potential difference.

FIG. 8 shows a detail from a schematic block diagram of the capacitivesensor devices 14 a and 14 b of the operator control device 10 accordingto the invention from FIG. 1, wherein, in contrast to the depiction inFIG. 7, which merely serves for explanation, the sensor structure 20 inthe case of the operator control device 10 according to the invention isadditionally connectable as a reference electrode 20 by means of theswitches SW4, SW5 and SW6 and can have a defined electrical potentialapplied to it, so that the capacitive coupling of the first sensorstructure 19 to a reference electrode, which in this case is formed bythe second sensor structure 20, can be registered, with a user input inthe detection area of the first sensor structure 19 causing aregisterable change, associated with the sensor structure 19, in acapacitive coupling C_(Ref) of the sensor structure 19 to the referenceelectrode 20 in comparison with the reference state.

In this case, it has been found to be particularly advantageous if thereference electrode 20 is connected in a further scanning cycle,particularly in a second scanning cycle AZ2 and/or a third and/or fourthscanning cycle, since this causes an increase in the potentialdifference ΔU₁ or ΔU₂ when the potential applied to the referenceelectrode 20 is chosen accordingly, as a result of which a betterresolution and hence a higher identification accuracy can be achieved.That is to say that the potential profiles U_(Sensor1) and U_(Sensor2)are then at a different level.

It is particularly advantageous if the change in the capacitive couplingof the sensor structure 19 to the surroundings and the change in thecapacitive coupling of the sensor structure 19 to the referenceelectrode 20 are registered in direct succession, in particular in turn,particularly preferably alternately. This allows a particularly highidentification accuracy to be achieved, since a multiplicity ofpotential values U_(Sensor1) and U_(Sensor2) or potential differencesΔU₁ and ΔU₂ are available that can be offset against one another almostarbitrarily in order to remove or compensate for measurement errors andsteady-state offsets or the like and/or to increase the resolution andhence the accuracy or sensitivity of the sensor device.

Preferably, the capacitive coupling of the first sensor structure 19 tothe surroundings and to a reference electrode, wherein the second sensorstructure 20 forms the reference electrode, and subsequently, but onlyat such slightly staggered times that plausibilization of the sensorsignals of the first and second sensor devices that is required forsafety-relevant functions continues to be possible, the capacitivecoupling of the second sensor structure 20 to the surroundings and to areference electrode, wherein in this case the first sensor structure 19forms the reference electrode, is registered in each case alternately inturn.

If an operator control device according to the invention has anadditional screening element, for example, as depicted in FIG. 4, in theform of a further electrical conductor 21 or a sensor structure operableas a screening element, then the screening element has a definedelectrical potential, particularly a potential U_(AE) tracked to orfollowing the potential applied to the relevant sensor structure, seeFIGS. 11 and 12, applied to it preferably during the registering of thecapacitive coupling of a sensor structure to the surroundings and/or toa reference electrode, FIG. 11 schematically showing an exemplary,advantageous profile of a tracked electrical potential U_(AE) that canbe applied to an active screening element.

In this case, the potential U_(AE) increases when the potentialU_(Sensor) applied to the sensor structure increases and decreases whenthe potential U_(Sensor) applied to the sensor structure decreases. Suchapplication of potentials to a screening element already allows goodscreening performance to be achieved.

A potential profile U_(AE) of this kind can be achieved through the useof a sensor system having a microcontroller from the “Microchip”company, for example, by virtue of the relevant screening element beingelectrically connected to an I/O pin provided specifically for thatpurpose on the microcontroller. The microcontroller is accordinglyconfigured to apply the shown potential profile to this pin on the basisof the state of the sensor device.

For even better screening, the defined electrical potential U_(AE)applied to the screening element should follow the electrical potentialU_(Sensor) applied to the sensor structure as well as possible,preferably as depicted in FIG. 12. FIG. 12 schematically shows theprofile of an electrical potential U_(AE) of an active screening elementthat has almost the same curved profile with almost the same absolutepotential values as the electrical potential U_(Sensor) applied to thesensor structure and therefore follows the profile of the electricalpotential U_(Sensor) applied to the sensor structure.

This potential profile U_(AE) can likewise be achieved by the use of asensor system having a microcontroller from the “Microchip” company, therelevant screening element in this case being connected to a differentpin provided for that purpose on the microcontroller, specifically towhat is known as the “DACOUT” pin. The microcontroller is accordinglyconfigured to apply the shown potential profile to this pin on the basisof the state of the sensor device.

Naturally, a multiplicity of modifications, in particular of designtype, are possible without departing from the content of the patentclaims.

The invention claimed is:
 1. An operator control device controllingsafety-relevant functions associated with a vehicle, the operatorcontrol device comprising: at least one user interface having at leastone user input panel for user input; and a sensor system for identifyinga user input in an area of the user input panel, wherein the sensorsystem comprises a first, capacitive sensor device having a first,electrically conductive sensor structure and a second, capacitive sensordevice having a second, electrically conductive sensor structure, thesensor structures being arranged beneath the at least one user interfacein the area of the user input panel wherein the first sensor structureand the second sensor structure are each configured in comb-like andmeanderous fashion and arranged in intermeshing fashion at least in asubarea of the user input panel, wherein the sensor system is configuredto register, in comparison with a reference state, a first electricalpotential change of the first sensor structure and a second electricalpotential change of the second sensor structure wherein the change inthe electrical potential is caused as a result of the user input in thearea of the user input panel, wherein the operator control devicetriggers one of the safety-relevant functions based on the sensor systemregistering the first electrical potential change and the secondelectrical potential change staggered times as a provision forsafety-relevant plausibilization of captured sensor signals, whereinregistering the first electrical potential change comprises:maintaining, throughout a first time period, the first sensor structureat a first constant electrical potential and a reference capacitor at asecond constant electrical potential; electrically connecting,throughout a second time period subsequent to the first time period, thefirst sensor structure and the reference capacitor together;registering, during a third time period subsequent to the second timeperiod, a first resulting electrical potential of the first sensorstructure; maintaining, throughout a fourth time period subsequent tothe third time period, the first sensor structure at the second constantelectrical potential and the reference capacitor at the first constantelectrical potential; electrically connecting, throughout a fifth timeperiod subsequent to the fourth time period, the first sensor structureand the reference capacitor together; registering, during a sixth timeperiod subsequent to the fifth time period, a second resultingelectrical potential of the first sensor structure, wherein the firstelectrical potential change comprises a difference between the firstresulting electrical potential and the second resulting electricalpotential.
 2. The operator control device according to claim 1, whereinthe at least one user interface has multiple user input panels eachhaving an associated sensor system for identifying a user input in thearea of the associated user input panel, wherein each sensor systemassociated with a user input panel has at least one first, capacitivesensor device having a first, electrically conductive sensor structureand a second, capacitive sensor device having a second, electricallyconductive sensor structure, the sensor structures each being arrangedbeneath the user interface of the associated user input panel, andwherein the first sensor structure and the second sensor structure areeach configured in comb-like and meanderous fashion and arranged inintermeshing fashion at least in a subarea of the associated user inputpanel.
 3. The operator control device according to claim 1, wherein: thesensor system is configured to register the change in the capacitivecoupling of at least one sensor structure to the surroundings, in afirst scanning cycle a reference capacitance and a measurementcapacitance, formed by the sensor structure and the surroundings, areeach charged with a defined electrical potential in a first step, thereference capacitance being charged with a first, defined electricalpotential and the measurement capacitance being charged with a second,defined electrical potential, the reference capacitance and themeasurement capacitance formed by the sensor structure and thesurroundings is shorted in a further second step, and the resultingelectrical potential arising between the measurement capacitance and thereference capacitance is registered as a sensor signal in a furtherthird step, the resulting electrical potential arising on the basis ofthe first and second electrical potentials, the magnitude of thereference capacitance and the magnitude of the measurement capacitance(C_(Surroundings)).
 4. The operator control device according to claim 3,wherein the sensor system is configured such that in a further scanningcycle, the reference capacitance is charged with the second electricalpotential and the measurement capacitance is charged with the firstelectrical potential in the first step, the reference capacitance andthe measurement capacitance (C_(Surroundings)) formed by the at leastone sensor structure and the surroundings are shorted in a furtherfourth step, and the resulting electrical potential arising between themeasurement capacitance and the reference capacitance is registered as asensor signal in a further fifth step, the resulting electricalpotential arising on the basis of the first and second potentials, ofthe magnitude of the reference capacitance and the magnitude of themeasurement capacitance.
 5. The operator control device according toclaim 1, wherein the reference capacitor comprises a reference electrodethat has a defined electrical potential applied to the referenceelectrode, and the sensor system is configured such that a user input inthe area of the user input panel causes a registerable change in acapacitive coupling of at least one sensor structure to the referenceelectrode in comparison with a reference state.
 6. The operator controldevice according to claim 5, wherein the sensor system is configuredsuch that in a further scanning cycle, the reference electrode has adefined electrical potential applied to it in a first step, and thecapacitive coupling of at least one sensor structure to the referenceelectrode can be registered in a further second step.
 7. The operatorcontrol device according to claim 1, wherein the sensor system isconfigured to register the change in the capacitive coupling of at leastone sensor structure to the surroundings and the change in thecapacitive coupling of this sensor structure to the reference capacitorin succession alternately.
 8. The operator control device according toclaim 1, wherein at least one sensor system has a screening devicehaving at least one screening element, wherein the screening device isconfigured to screen the first sensor device or the second sensor devicefrom perturbing capacitive couplings to components of the operatorcontrol device, the screening element being formed by an electricallyconductive screening structure that is arranged between the first sensorstructure of the first sensor device and the second sensor structure ofthe second sensor device of the sensor system.
 9. The operator controldevice according to claim 8, wherein the screening element can have adefined, electrical potential, that is at least sometimes tracked to apotential applied to the sensor structure during the registering of thechange in the capacitive coupling of the sensor structure wherein thepotential follows the profile of the potential applied to the sensorstructure during registering of the change in the capacitive coupling ofa sensor structure of the sensor system.
 10. The operator control deviceaccording to claim 9, wherein at least one sensor structure of at leastone sensor system can also be connected as an active screening element,wherein the first sensor structure and the second sensor structure caneach be connected as an active screening element in turn.
 11. Theoperator control device according to claim 1, wherein at least onesensor system has not only the first capacitive sensor device and thesecond capacitive sensor device but also at least one further sensordevice for identifying a user input in the area of the user input panelassociated with the sensor system.
 12. The operator control deviceaccording to claim 1, wherein at least one sensor system is configuredto register the change in the capacitive coupling of the sensorstructure of a capacitive sensor device to the surroundings or to thereference electrode capacitor only if a user input has been identifiedbeforehand during the registering of the change in the capacitivecoupling of the sensor structure of the other sensor device to thesurroundings or to the reference electrode capacitor.
 13. The operatorcontrol device according to claim 1, further comprising a monitoringdevice for identifying a fault state in at least one sensor system,wherein the monitoring device is configured to plausibilize at least onecaptured sensor signal of at least one sensor device of the sensorsystem, to plausibilize the sensor signals of all of the sensor devicesof the sensor system, wherein the monitoring device identifies a faultif at least one captured and evaluated sensor signal of the sensorsystem is implausible, the monitoring device being configured to take atleast one captured sensor signal of the first sensor device and at leastone captured sensor signal of the second sensor device and to take thedirectly successively registered changes in the capacitive coupling of asensor structure to the surroundings and in the capacitive coupling ofthis sensor structure to the reference electrode capacitor as a basisfor identifying whether there is a fault state.
 14. The operator controldevice according to claim 1, wherein the operator control device has alighting device having at least one light-emitting source for lightingthe back of at least one user input panel, wherein the at least onelight-emitting source is arranged in a plane beneath at least one sensorstructure of the sensor system associated with the control panel,beneath the sensor structure of the first capacitive sensor device andbeneath the sensor structure of the second capacitive sensor device ofthe sensor system associated with the control panel.
 15. The operatorcontrol device according to claim 14, wherein all the sensor structuresof the sensor system are arranged such that a beam path from the atleast one light-emitting source to the user input panel is not blocked.16. The operator control device according to claim 14, wherein all thestructures of the sensor system including the first and second sensorstructures, are configured in such a transparent fashion that they aretransmissive at least for a portion of the radiation emitted by the atleast one light-emitting source.
 17. The operator control deviceaccording to claim 14, wherein at least one sensor structure comprisesor is manufactured from indium tin oxide, fluorine-doped tin oxide,aluminium-doped tin oxide, antimony-doped tin oxide or graphene.
 18. Amethod for operating an operator control device that is configuredaccording to claim 1, wherein the operator control device has at leastone user interface having at least one user input panel for user inputand a sensor system for identifying user input in the area of the userinput panel, wherein the sensor system has at least one first,capacitive sensor device having a first, electrically conductive sensorstructure and a second, capacitive sensor device having a second,electrically conductive sensor structure, the sensor structures beingarranged beneath the user interface in the area of the user input panel,the method comprising: to identify a user input, registering the changein the capacitive coupling of the first sensor structure to thesurroundings or the reference electrode and a change in the capacitivecoupling of the second sensor structure to the surroundings or thereference electrode, wherein registering the change in the capacitivecoupling of at least one sensor structure to the surroundings comprises,in a first scanning cycle, charging each of a reference capacitance anda measurement capacitance, formed by the sensor structure and thesurroundings with a defined electrical potential; charging the referencecapacitance with a first, defined electrical potential and themeasurement capacitance being charged with a second, defined electricalpotential, in a first step; shorting the reference capacitance and themeasurement capacitance formed by the sensor structure and thesurroundings are shorted in a further second step; and registering theresulting electrical potential arising between the measurementcapacitance and the reference capacitance is registered as a sensorsignal in a further third step, the resulting electrical potentialarising on the basis of the first and second electrical potentials andalso on the basis of the magnitude of the reference capacitance and onthe basis of the magnitude of the measurement capacitance.
 19. Themethod according to claim 18, further comprising, in a further secondscanning cycle, charging the reference capacitance with the secondelectrical potential and charging the measurement capacitance with thefirst electrical potential in the first step, shorting the referencecapacitance and the measurement capacitance formed by the at least onesensor structure and the surroundings in a further fourth step, andregistering the resulting electrical potential arising between themeasurement capacitance and the reference capacitance as a sensor signalin a further fifth step, the resulting electrical potential arising onthe basis of the first and second potentials and also on the basis ofthe magnitude of the reference capacitance and on the basis of themagnitude of the measurement capacitance.
 20. The method according toclaim 18, wherein the sensor system is configured such that a user inputin the area of the user input panel causes a registerable change in acapacitive coupling of at least one sensor structure to the referenceelectrode in comparison with a reference state, wherein, in a furtherscanning cycle, the reference electrode has a defined electricalpotential applied to it in a first step, and the capacitive coupling ofthe sensor structure to the reference electrode is registered in afurther step.
 21. The method according to claim 18, wherein at least onesensor system has a screening device having at least one electricallyconductive screening element for screening the first sensor device andthe second sensor device from perturbing capacitive couplings tocomponents of the operator control device, wherein the screening elementhas a defined, electrical potential that is at least sometimes trackedto a potential that is applied to the sensor structure during theregistering of the change in the capacitive coupling of the sensorstructure, wherein the electrical potential follows the profile of thepotential applied to the sensor structure, applied to it duringregistering of the change in the capacitive coupling of at least onesensor structure of the sensor system.
 22. The method according to claim21, wherein both sensor structures of at least one sensor system isintermittently operated in turn as an active screening element.
 23. Themethod according to claim 18, wherein at least the change in thecapacitive coupling of the sensor structure of the first capacitivesensor device and of the sensor structure of the second sensor device ofthe sensor system to the surroundings or to the reference electrode areregistered staggered times as a provision for safety-relevantplausibilization of the captured sensor signals, wherein a user input ina user input panel is registered by all the sensor devices of the sensorsystem of the associated user input panel at staggered times.
 24. Themethod according to at least claim 18, wherein the change in thecapacitive coupling of the sensor structure of a sensor device to thesurroundings or to the reference electrode is registered only when auser input has been identified beforehand during the registering of thechange in the capacitive coupling of the sensor structure of the othersensor device to the surroundings or to the reference electrode.
 25. Themethod according to claim 18, wherein when a user input on a user inputpanel is identified, a function associated with the user input panel istriggered only if no fault state in the sensor system has beenidentified.
 26. The method according to claim 25, wherein the userinterface has multiple user input panels, wherein each user input panelhas an associated sensor system for identifying a user input in the areaof the associated user input panel, wherein each sensor systemassociated with a user input panel has at least one first, capacitivesensor device having a first, electrically conductive sensor structureand a second, capacitive sensor device having a second, electricallyconductive sensor structure, the sensor structures each being arrangedbeneath the user interface of the associated user input panel, whereinwhen a user input has been identified, a function is triggered only if auser input has been identified only in a single user input panel. 27.The method according to claim 18, wherein the operator control devicehas a monitoring device for identifying a fault state in at least onesensor system, wherein the monitoring device is used to plausibilize atleast one sensor signal of at least one sensor device of at least onesensor system, wherein a fault state is identified if at least onecaptured and evaluated sensor signal is implausible, a fault state beingidentified if at least one captured sensor signal of the first sensordevice is implausible by comparison with at least one captured sensorsignal of the second sensor device or if the directly successivelyregistered changes in the capacitive coupling of at least one sensorstructure to the surroundings and in the capacitive coupling of thissensor structure to the reference electrode are implausible.
 28. Theoperator control device according to claim 4, wherein registering thesecond electrical potential change comprises: maintaining, throughout aseventh time period, the second sensor structure at the first constantelectrical potential and the reference capacitor at the second constantelectrical potential; electrically connecting, throughout an eighth timeperiod subsequent to the seventh time period, the second sensorstructure and the reference capacitor together; registering, during aninth time period subsequent to the eighth time period, a thirdresulting electrical potential of the second sensor structure;maintaining, throughout a tenth time period subsequent to the ninth timeperiod, the second sensor structure at the second constant electricalpotential and the reference capacitor at the first constant electricalpotential; electrically connecting, throughout an eleventh time periodsubsequent to the tenth time period, the second sensor structure and thereference capacitor together; and registering, during a twelfth timeperiod subsequent to the eleventh time period, a fourth resultingelectrical potential of the second sensor structure, wherein the secondelectrical potential change comprises a difference between the thirdresulting electrical potential and the fourth resulting electricalpotential.